T-square



E. D. EFSTRATIADES.

T-SQUARE. v APPLICATION FIL'ED AUG- 10, 1920.

1,389,864. Patentedsept- 6, 1921.

PATENT OFFICE.

EUS'I'ACE D. EFSTRATIADES, 0F NEXVARK, NEW JERSEY.

T-SQUARE.

Specification of Letters Patent.

Patented Sept. 6, 1921.

Application filed August 10, 1920. Serial No. 402,515.

To all whom it may concern.

Be it known that I, EUsTAcE D. EFSTRA- TIADES, a citizen of Greece, residing at Newark, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in T-Squares; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in T-squares and more particularly to adjustable T-squares.

One object of the invention is to provide an adjustable T-square which is simple and durable in construction and which may be manufactured at a comparatively low cost.

Another object is to provide an adjustable T-square with which angles can be quickly and easily measured and-laid off.

Other objects and advantages will be apparent from the following description, when taken in connection with the accompanying drawing.

In the drawing:

Figure 1 is a plan view of a T-square having my invention incorporated therein,

a portion of the leg of the T being broken off.

Fig. 2 is an end elevation taken from the end to the left in Fig. 1.

Fig. 3 is a vertical transverse sectional view on the line 33 of Fig. l, slightly enlarged.

Fig. l is a horizontal sectional view on the line 4-4: of Fig. 2.

Fig. 5 is a fragmentary plan view of the T-square showing the same in adjusted position.

Fig. 6 is a longitudinal sectional view on the line 6-6 of Fig. 1.

Referring particularly to the accompanying drawing, 10 represents the head of the T-square and'll the leg or blade thereof, which is pivotally connected to the head. Formed centrally of the longitudinal dimension of the head, and near one edge is an opening 12, and in the upper face of the head and surrounding the opening is formed a rectangular recess 13. Disposed through this opening 12 is a tubular member 14 which carries a flange 15 of the same size and configuration as the recess 13 so that the upper face of the flange will be flush with the face of the head. This flange is secured within the recess in any suitable manner, but preferably by means of a bolt 16 and nut 17, this bolt projecting through the lower side of the head and having the nut applied to its end and turned against the under face of the head. This bolt forms an integral part of a block 18 secured in the lower portion of the member 14 by means of a cross piece 19. The upper end of the tubular member lat is formed with the diametrically opposite and vertical open ended slots 20 in which is slidably disposed a cross arm 21. This cross arm 21 has a cen tral circular portion 22- formed with a threadedopening23, and is connected to the end portions by means of the reduced necks 2 1. Threaded vertically through the opening 23 is a screw 25, the upper end of which carries a milled head 26 by means of which the screw can be turned. The lower end of the screw 25 is rotatably held in the upper end of the block 18, so that upon rotation of the screw in either direction, the screw will remain stationary against longitudinal movement, but cause the cross arm 21 to travel up and down thereon.

The inner end of the blade 11 is formed with an opening 27 to snugly receive the upper portion of the cylindrical member 14 and to rest on the flange 15 below the lower ends of the slots 20. On the upper portion of the apertured end of the blade is an arcuate extension 28, and secured to this arcuate extension is a protractor scale 29, said scale being either marked directly on the blade or formed of such materials as celluloid, metal or the like and secured thereto. On one of the outer ends of the cross arm 21 is secured a longitudinally extending needle 30 which'is disposed over the graduations of the protractor scale. The under face of the cross arm 21 is scored so as to bite into the upper face of the head and prevent relative movements of the head and blade when the parts are clamped together.

Upon rotation of the screw 25 in one direction, the cross arm 21 will be raised from the leg so that the leg may be swung to bring the desired degree mark of the scale 29 under the point of the needle 30. When this has been accomplished the screw 25 is turned in the opposite direction and the cross-arm forced tightly against the leg.

From the foregoing it will be seen that I have provided 'a simple and efiicient device by means of which various angles can be quickly measured or laid off.

What is claimed; is

1'. A T-square including a head and a leg pivotally connected thereto, of a protractor scale mounted on the leg and extending over the head, a clamping arm for holding the leg in adjusted positions,

I and'a needle point carried by the arm and arranged to traverse the protracter scale. I 2. A T-square including a head and a leg,

' the head and leg having registering openings, a cylindrical member disposed in the head opening and projecting through the leg opening, means for detachably clamping the cylindrical member to the head, the upper portion of the cylindrical member having diametrically opposite open ended slots,v a 7 transverse arm having a central circular portion slidably disposedinthe upper portion of the tubular member and projecting through the slots, a protractor scale carried by the leg concentric with the opening therein, and a vertical screw threaded through the said circular portion of the arm for raising and lowering the said arm away from and toward the leg, said arm having a needle point at one end arranged to traverse the protractor'scale. r

In testimony whereof, I aflix my signature;

in'the presenceof two witnesses.

EUSTAGE n.v EFS TRA TIADES.

Witnesses: V 7

ELLAS G. ELIoroULos, E. RHAMBIOHL 

